drivers/power/supply/sbs-manager.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for SBS compliant Smart Battery System Managers
   4  *
   5  * The device communicates via i2c at address 0x0a and multiplexes access to up
   6  * to four smart batteries at address 0x0b.
   7  *
   8  * Via sysfs interface the online state and charge type are presented.
   9  *
  10  * Datasheet SBSM:    http://sbs-forum.org/specs/sbsm100b.pdf
  11  * Datasheet LTC1760: http://cds.linear.com/docs/en/datasheet/1760fb.pdf
  12  *
  13  * Karl-Heinz Schneider <karl-heinz@schneider-inet.de>
  14  */
  15
  16 #include <linux/gpio/driver.h>
  17 #include <linux/module.h>
  18 #include <linux/i2c.h>
  19 #include <linux/i2c-mux.h>
  20 #include <linux/power_supply.h>
  21 #include <linux/property.h>
  22
  23 #define SBSM_MAX_BATS  4
  24 #define SBSM_RETRY_CNT 3
  25
  26 /* registers addresses */
  27 #define SBSM_CMD_BATSYSSTATE     0x01
  28 #define SBSM_CMD_BATSYSSTATECONT 0x02
  29 #define SBSM_CMD_BATSYSINFO      0x04
  30 #define SBSM_CMD_LTC             0x3c
  31
  32 #define SBSM_MASK_BAT_SUPPORTED  GENMASK(3, 0)
  33 #define SBSM_MASK_CHARGE_BAT     GENMASK(7, 4)
  34 #define SBSM_BIT_AC_PRESENT      BIT(0)
  35 #define SBSM_BIT_TURBO           BIT(7)
  36
  37 #define SBSM_SMB_BAT_OFFSET      11
  38 struct sbsm_data {
  39         struct i2c_client *client;
  40         struct i2c_mux_core *muxc;
  41
  42         struct power_supply *psy;
  43
  44         u8 cur_chan;          /* currently selected channel */
  45         struct gpio_chip chip;
  46         bool is_ltc1760;      /* special capabilities */
  47
  48         unsigned int supported_bats;
  49         unsigned int last_state;
  50         unsigned int last_state_cont;
  51 };
  52
  53 static enum power_supply_property sbsm_props[] = {
  54         POWER_SUPPLY_PROP_ONLINE,
  55         POWER_SUPPLY_PROP_CHARGE_TYPE,
  56 };
  57
  58 static int sbsm_read_word(struct i2c_client *client, u8 address)
  59 {
  60         int reg, retries;
  61
  62         for (retries = SBSM_RETRY_CNT; retries > 0; retries--) {
  63                 reg = i2c_smbus_read_word_data(client, address);
  64                 if (reg >= 0)
  65                         break;
  66         }
  67
  68         if (reg < 0) {
  69                 dev_err(&client->dev, "failed to read register 0x%02x\n",
  70                         address);
  71         }
  72
  73         return reg;
  74 }
  75
  76 static int sbsm_write_word(struct i2c_client *client, u8 address, u16 word)
  77 {
  78         int ret, retries;
  79
  80         for (retries = SBSM_RETRY_CNT; retries > 0; retries--) {
  81                 ret = i2c_smbus_write_word_data(client, address, word);
  82                 if (ret >= 0)
  83                         break;
  84         }
  85         if (ret < 0)
  86                 dev_err(&client->dev, "failed to write to register 0x%02x\n",
  87                         address);
  88
  89         return ret;
  90 }
  91
  92 static int sbsm_get_property(struct power_supply *psy,
  93                              enum power_supply_property psp,
  94                              union power_supply_propval *val)
  95 {
  96         struct sbsm_data *data = power_supply_get_drvdata(psy);
  97         int regval = 0;
  98
  99         switch (psp) {
 100         case POWER_SUPPLY_PROP_ONLINE:
 101                 regval = sbsm_read_word(data->client, SBSM_CMD_BATSYSSTATECONT);
 102                 if (regval < 0)
 103                         return regval;
 104                 val->intval = !!(regval & SBSM_BIT_AC_PRESENT);
 105                 break;
 106
 107         case POWER_SUPPLY_PROP_CHARGE_TYPE:
 108                 regval = sbsm_read_word(data->client, SBSM_CMD_BATSYSSTATE);
 109                 if (regval < 0)
 110                         return regval;
 111
 112                 if ((regval & SBSM_MASK_CHARGE_BAT) == 0) {
 113                         val->intval = POWER_SUPPLY_CHARGE_TYPE_NONE;
 114                         return 0;
 115                 }
 116                 val->intval = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
 117
 118                 if (data->is_ltc1760) {
 119                         /* charge mode fast if turbo is active */
 120                         regval = sbsm_read_word(data->client, SBSM_CMD_LTC);
 121                         if (regval < 0)
 122                                 return regval;
 123                         else if (regval & SBSM_BIT_TURBO)
 124                                 val->intval = POWER_SUPPLY_CHARGE_TYPE_FAST;
 125                 }
 126                 break;
 127
 128         default:
 129                 return -EINVAL;
 130         }
 131
 132         return 0;
 133 }
 134
 135 static int sbsm_prop_is_writeable(struct power_supply *psy,
 136                                   enum power_supply_property psp)
 137 {
 138         struct sbsm_data *data = power_supply_get_drvdata(psy);
 139
 140         return (psp == POWER_SUPPLY_PROP_CHARGE_TYPE) && data->is_ltc1760;
 141 }
 142
 143 static int sbsm_set_property(struct power_supply *psy,
 144                              enum power_supply_property psp,
 145                              const union power_supply_propval *val)
 146 {
 147         struct sbsm_data *data = power_supply_get_drvdata(psy);
 148         int ret = -EINVAL;
 149         u16 regval;
 150
 151         switch (psp) {
 152         case POWER_SUPPLY_PROP_CHARGE_TYPE:
 153                 /* write 1 to TURBO if type fast is given */
 154                 if (!data->is_ltc1760)
 155                         break;
 156                 regval = val->intval ==
 157                          POWER_SUPPLY_CHARGE_TYPE_FAST ? SBSM_BIT_TURBO : 0;
 158                 ret = sbsm_write_word(data->client, SBSM_CMD_LTC, regval);
 159                 break;
 160
 161         default:
 162                 break;
 163         }
 164
 165         return ret;
 166 }
 167
 168 /*
 169  * Switch to battery
 170  * Parameter chan is directly the content of SMB_BAT* nibble
 171  */
 172 static int sbsm_select(struct i2c_mux_core *muxc, u32 chan)
 173 {
 174         struct sbsm_data *data = i2c_mux_priv(muxc);
 175         struct device *dev = &data->client->dev;
 176         int ret = 0;
 177         u16 reg;
 178
 179         if (data->cur_chan == chan)
 180                 return ret;
 181
 182         /* chan goes from 1 ... 4 */
 183         reg = BIT(SBSM_SMB_BAT_OFFSET + chan);
 184         ret = sbsm_write_word(data->client, SBSM_CMD_BATSYSSTATE, reg);
 185         if (ret)
 186                 dev_err(dev, "Failed to select channel %i\n", chan);
 187         else
 188                 data->cur_chan = chan;
 189
 190         return ret;
 191 }
 192
 193 static int sbsm_gpio_get_value(struct gpio_chip *gc, unsigned int off)
 194 {
 195         struct sbsm_data *data = gpiochip_get_data(gc);
 196         int ret;
 197
 198         ret = sbsm_read_word(data->client, SBSM_CMD_BATSYSSTATE);
 199         if (ret < 0)
 200                 return ret;
 201
 202         return ret & BIT(off);
 203 }
 204
 205 /*
 206  * This needs to be defined or the GPIO lib fails to register the pin.
 207  * But the 'gpio' is always an input.
 208  */
 209 static int sbsm_gpio_direction_input(struct gpio_chip *gc, unsigned int off)
 210 {
 211         return 0;
 212 }
 213
 214 static int sbsm_do_alert(struct device *dev, void *d)
 215 {
 216         struct i2c_client *client = i2c_verify_client(dev);
 217         struct i2c_driver *driver;
 218
 219         if (!client || client->addr != 0x0b)
 220                 return 0;
 221
 222         device_lock(dev);
 223         if (client->dev.driver) {
 224                 driver = to_i2c_driver(client->dev.driver);
 225                 if (driver->alert)
 226                         driver->alert(client, I2C_PROTOCOL_SMBUS_ALERT, 0);
 227                 else
 228                         dev_warn(&client->dev, "no driver alert()!\n");
 229         } else {
 230                 dev_dbg(&client->dev, "alert with no driver\n");
 231         }
 232         device_unlock(dev);
 233
 234         return -EBUSY;
 235 }
 236
 237 static void sbsm_alert(struct i2c_client *client, enum i2c_alert_protocol prot,
 238                        unsigned int d)
 239 {
 240         struct sbsm_data *sbsm = i2c_get_clientdata(client);
 241
 242         int ret, i, irq_bat = 0, state = 0;
 243
 244         ret = sbsm_read_word(sbsm->client, SBSM_CMD_BATSYSSTATE);
 245         if (ret >= 0) {
 246                 irq_bat = ret ^ sbsm->last_state;
 247                 sbsm->last_state = ret;
 248                 state = ret;
 249         }
 250
 251         ret = sbsm_read_word(sbsm->client, SBSM_CMD_BATSYSSTATECONT);
 252         if ((ret >= 0) &&
 253             ((ret ^ sbsm->last_state_cont) & SBSM_BIT_AC_PRESENT)) {
 254                 irq_bat |= sbsm->supported_bats & state;
 255                 power_supply_changed(sbsm->psy);
 256         }
 257         sbsm->last_state_cont = ret;
 258
 259         for (i = 0; i < SBSM_MAX_BATS; i++) {
 260                 if (irq_bat & BIT(i)) {
 261                         device_for_each_child(&sbsm->muxc->adapter[i]->dev,
 262                                               NULL, sbsm_do_alert);
 263                 }
 264         }
 265 }
 266
 267 static int sbsm_gpio_setup(struct sbsm_data *data)
 268 {
 269         struct gpio_chip *gc = &data->chip;
 270         struct i2c_client *client = data->client;
 271         struct device *dev = &client->dev;
 272         int ret;
 273
 274         if (!device_property_present(dev, "gpio-controller"))
 275                 return 0;
 276
 277         ret  = sbsm_read_word(client, SBSM_CMD_BATSYSSTATE);
 278         if (ret < 0)
 279                 return ret;
 280         data->last_state = ret;
 281
 282         ret  = sbsm_read_word(client, SBSM_CMD_BATSYSSTATECONT);
 283         if (ret < 0)
 284                 return ret;
 285         data->last_state_cont = ret;
 286
 287         gc->get = sbsm_gpio_get_value;
 288         gc->direction_input  = sbsm_gpio_direction_input;
 289         gc->can_sleep = true;
 290         gc->base = -1;
 291         gc->ngpio = SBSM_MAX_BATS;
 292         gc->label = client->name;
 293         gc->parent = dev;
 294         gc->owner = THIS_MODULE;
 295
 296         ret = devm_gpiochip_add_data(dev, gc, data);
 297         if (ret)
 298                 return dev_err_probe(dev, ret, "devm_gpiochip_add_data failed\n");
 299
 300         return ret;
 301 }
 302
 303 static const struct power_supply_desc sbsm_default_psy_desc = {
 304         .type = POWER_SUPPLY_TYPE_MAINS,
 305         .properties = sbsm_props,
 306         .num_properties = ARRAY_SIZE(sbsm_props),
 307         .get_property = &sbsm_get_property,
 308         .set_property = &sbsm_set_property,
 309         .property_is_writeable = &sbsm_prop_is_writeable,
 310 };
 311
 312 static void sbsm_del_mux_adapter(void *data)
 313 {
 314         struct sbsm_data *sbsm = data;
 315         i2c_mux_del_adapters(sbsm->muxc);
 316 }
 317
 318 static int sbsm_probe(struct i2c_client *client)
 319 {
 320         const struct i2c_device_id *id = i2c_client_get_device_id(client);
 321         struct i2c_adapter *adapter = client->adapter;
 322         struct sbsm_data *data;
 323         struct device *dev = &client->dev;
 324         struct power_supply_desc *psy_desc;
 325         struct power_supply_config psy_cfg = {};
 326         int ret = 0, i;
 327
 328         /* Device listens only at address 0x0a */
 329         if (client->addr != 0x0a)
 330                 return -EINVAL;
 331
 332         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 333                 return -EPFNOSUPPORT;
 334
 335         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 336         if (!data)
 337                 return -ENOMEM;
 338
 339         i2c_set_clientdata(client, data);
 340
 341         data->client = client;
 342         data->is_ltc1760 = !!strstr(id->name, "ltc1760");
 343
 344         ret  = sbsm_read_word(client, SBSM_CMD_BATSYSINFO);
 345         if (ret < 0)
 346                 return ret;
 347         data->supported_bats = ret & SBSM_MASK_BAT_SUPPORTED;
 348         data->muxc = i2c_mux_alloc(adapter, dev, SBSM_MAX_BATS, 0,
 349                                    I2C_MUX_LOCKED, &sbsm_select, NULL);
 350         if (!data->muxc)
 351                 return dev_err_probe(dev, -ENOMEM, "failed to alloc i2c mux\n");
 352         data->muxc->priv = data;
 353
 354         ret = devm_add_action_or_reset(dev, sbsm_del_mux_adapter, data);
 355         if (ret)
 356                 return ret;
 357
 358         /* register muxed i2c channels. One for each supported battery */
 359         for (i = 0; i < SBSM_MAX_BATS; ++i) {
 360                 if (data->supported_bats & BIT(i)) {
 361                         ret = i2c_mux_add_adapter(data->muxc, 0, i + 1, 0);
 362                         if (ret)
 363                                 break;
 364                 }
 365         }
 366         if (ret)
 367                 return dev_err_probe(dev, ret, "failed to register i2c mux channel %d\n", i + 1);
 368
 369         psy_desc = devm_kmemdup(dev, &sbsm_default_psy_desc, sizeof(*psy_desc), GFP_KERNEL);
 370         if (!psy_desc)
 371                 return -ENOMEM;
 372
 373         psy_desc->name = devm_kasprintf(dev, GFP_KERNEL, "sbsm-%s", dev_name(&client->dev));
 374         if (!psy_desc->name)
 375                 return -ENOMEM;
 376
 377         ret = sbsm_gpio_setup(data);
 378         if (ret < 0)
 379                 return ret;
 380
 381         psy_cfg.drv_data = data;
 382         psy_cfg.of_node = dev->of_node;
 383         data->psy = devm_power_supply_register(dev, psy_desc, &psy_cfg);
 384         if (IS_ERR(data->psy))
 385                 return dev_err_probe(dev, PTR_ERR(data->psy),
 386                                      "failed to register power supply %s\n", psy_desc->name);
 387
 388         return 0;
 389 }
 390
 391 static const struct i2c_device_id sbsm_ids[] = {
 392         { "sbs-manager", 0 },
 393         { "ltc1760",     0 },
 394         { }
 395 };
 396 MODULE_DEVICE_TABLE(i2c, sbsm_ids);
 397
 398 #ifdef CONFIG_OF
 399 static const struct of_device_id sbsm_dt_ids[] = {
 400         { .compatible = "sbs,sbs-manager" },
 401         { .compatible = "lltc,ltc1760" },
 402         { }
 403 };
 404 MODULE_DEVICE_TABLE(of, sbsm_dt_ids);
 405 #endif
 406
 407 static struct i2c_driver sbsm_driver = {
 408         .driver = {
 409                 .name = "sbsm",
 410                 .of_match_table = of_match_ptr(sbsm_dt_ids),
 411         },
 412         .probe          = sbsm_probe,
 413         .alert          = sbsm_alert,
 414         .id_table       = sbsm_ids
 415 };
 416 module_i2c_driver(sbsm_driver);
 417
 418 MODULE_LICENSE("GPL");
 419 MODULE_AUTHOR("Karl-Heinz Schneider <karl-heinz@schneider-inet.de>");
 420 MODULE_DESCRIPTION("SBSM Smart Battery System Manager");